1. Field of the Invention
The present invention relates to a door window regulator which vertically moves and guides a door window glass of an automobile.
2. Description of the Prior Art
In general, a door window regulator has an X-shaped arm made from steel sheet and is arranged such that a door window glass mounted on the upper end of the X-shaped arm is vertically moved by the pivoting of the X-shaped arm. The door window regulator employing such an X-shaped arm has a relatively large weight and a relatively large moving locus, which fact disadvantageously limits the range of available configurations and structures of the door.
In view of this fact, door window regulators have heretofore been proposed in which a wire is employed as a window glass driving means mainly from the viewpoint of reducing the weight of the apparatus.
As one example of such conventional door window regulators, a structure has been proposed in the specification of U. S.Pat. No. 4,109,417 in which a wire is passed over pulleys which are rotatably supported at the respective upper and lower portions of a guide thereby to apply actuating force to a window glass by means of which it is raised and lowered. In this type of window regulator, however, the wire between the pulleys extends in straight line form and is therefore located closer to the inside of the compartment than the guide when the window glass is at its maximumly raised position, which fact requires the door to have a disadvantageously large thickness, and it is difficult to provide a cavity on the inner side of the door or apply a proper three-dimensional shaping to the door trim which serves as a door lining for the purpose of coping with an increase in the thickness of the door and increasing the space inside the compartment as much as possible.
In recent automobiles particularly, the radius of curvature of the window glass is reduced for the purpose of increasing the space inside the compartment, and the radius of curvature of the guide is also correspondingly reduced, which fact disadvantageously leads to an increase in the degree to which the wire is located closer to the inside of the compartment than the guide when the window glass is at its maximumly raised position.
A window regulator having a structure similar to the above is disclosed in the specification of German Patent Laid-Open No. 3,108,557, in which the guide is deflected toward the outside of the compartment. With this structure, however, the angle at which the wire is passed over a pulley is undesirably changed by the vertical movement of the window glass, which involves force acting on the pulley in the direction of thrust, causing an increase in the frictional resistance.
Window regulators which are shown in the specifications of Japanese Patent Laid-Open No. 161,173/1980 and Japanese Utility-Model Laid-Open No. 41,996/1980 are arranged such that a wire is disposed and moved within a guide. This arrangement, however, undesirably involves an increase in the widthwise dimension of the guide and a complicated structure for a slider. Additionally, the frictional resistance is disadvantageously large, which fact unfavorably leads to generation of rust.